My, didn't Britain argue in 2006! And how British "tolerance" toughened up! No more Mr Nice Guy, oh no. There was the row over the hijab and niqab and demands to conform to "British" norms (though faith schools further entrenched social division). ID cards were championed to protect citizens' identities (but slammed for curtailing their liberties). We had Islamism and Islamophobia; Eastern Europeans and Western racism; hoodie hugging and snobbish snubbing; gay marriage and gay bashing; multiculturalism versus integration. And now, exhausted, we ask: what can be done for British cohesion in 2007?

The trouble is that we have no definable British identity around which to unite. Celebrants of diversity may enjoy the variety that characterises British life, but difference can never unite us - it would be a flimsy unifying factor on which to depend. At its best, multiculturalism presents a colligation of paradigms to be admired; at worst, difference begets intolerance, mistrust and division.

On the other hand, those promulgating new, integrationist policies are equally missing the point. 2006 was the year of the Britishness test. White Britons, it seems, are tired of people coming here and refusing to play cricket. But they ignore the fact that immigration is not just about providing people with new homes and identities. It is a two-way street and, like it or not, every immigrant that comes to Britain fundamentally influences Britishness itself.

Just as the face of Britain has changed, so has its identity. To privilege traditional British customs and history over those of newer sections of society is to overlook this. British identity doesn't reside in a limitless pluralism, making it at once everything and nothing, but nor does it lie with traditional Anglo-Saxon society. Instead, Britishness now stands somewhere between a range of diverse social groupings. White, traditional Britain must move towards this medium like any other section of society.

And yet there is currently no marker for where this new identity lies. In fact, it has not yet been created. To pluck an identity from the air is futile - not only will it be impossible to agree on a medium, but it will be so abstract as to be unattainable. Instead, it is physical institutions that give individuals a common identity, binding them to the state. Immigrants often claim that the first truly British generation of their family is the one educated here - schools offer a shared experience to all attendees that is, by definition, British.

However, private, faith and grammar schools mean that, even at school, children are often divided along class and religious lines. Frequently, children leave school as underexposed to Britain's diversity as when they entered. After school, it is no better. There is university (largely for the privileged) and beyond that, the work place - by which time divisions are well and truly petrified.

The fact is that there is no truly unifying British institutional experience.

And so we must create one. A new institution must be established to realise and solidify the emergent British identity. An institution that unites the disparate elements of society with a shared experience that is British both in its make-up and in its purpose. It is for this reason that we must bring back national service.

Now that might have hurt, but after the initial prick, you might find the remedy surprisingly effective. Firstly, let's be clear, I am not talking about national military service, but rather national social or community service, in whatever form that might take - from working with the aged, the homeless and new immigrants to working in hospitals, schools and public services. I am, however, calling for a period of compulsory national service for all school-leavers. Social division must be countered by social inclusion and there is no better time to build bridges than during childhood.

At the age when the richest children jet off to Thailand while the poorest gather, gloomy on street corners; when many orthodox Jews disappear into yeshiva, some Muslims turn to isolationism and certain whites turn to the BNP; when elements of ghettoised communities reach their most disenchanted and dangerous as the rich escape to ivory towers, what better way to help an entire generation than to bring them together in important community work?

Crucially, this service would include every youth in Britain, regardless of race, religion, origin or background. And in this shared experience, an entire generation of Britons will have a common point of reference to form the cornerstone of a new British identity.

It might sound utopian, perhaps even draconian now, but that just shows how individualistic we have become. After all, Thatcher taught us well that there is no such thing as society. In time, though, national service could become the standard for British youth, who could unlearn our lessons and rediscover that society includes everyone.

And as the make-up of British society changes, so too will the demographic of the national service intake. Different elements will go in, and an ever-changing compound will emerge. But it will always be, by definition, British. Thus national identity will no longer be an abstract concept - it will create itself.

After all, no man is an island, but this is an island of many different men and women, and without something to unite us, well - if you thought 2006 was bad ...